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光纤光栅传感器对非均匀应变场的响应特性 被引量:4
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作者 高超干 白瑜芳 +1 位作者 梁大开 周储伟 《南京航空航天大学学报》 EI CAS CSCD 北大核心 2020年第5期800-807,共8页
提出利用测量位置处光栅传感器的光谱特征反推该处对应的应变分布状态的方法。采用改进的传递矩阵方法,模拟了不同应变分布函数对应的光谱响应,分析了其基本特征参数同应变分布之间的变化规律。通过有限元仿真计算试验件在弯曲载荷下光... 提出利用测量位置处光栅传感器的光谱特征反推该处对应的应变分布状态的方法。采用改进的传递矩阵方法,模拟了不同应变分布函数对应的光谱响应,分析了其基本特征参数同应变分布之间的变化规律。通过有限元仿真计算试验件在弯曲载荷下光栅粘贴处的应变分布,重构了传感器的光谱,并将其和应变分布函数的理论计算光谱图进行比较,验证了应变分布形式与反射光谱特征的关联性。构建带有不同半径圆孔的铝合金板孔口弯曲加载试验系统,测试试验件弯曲挠度和孔径大小与反射谱特性的关系。理论及试验结果表明,实测与仿真计算的谱图变化具有相同规律,光谱特征参数可作为预测铝合金孔径的有效指标,并为其他类型结构的应变场变化规律的监测提供参考依据。 展开更多
关键词 光谱响应分析 非均匀应变分布 有限元方法 光谱特征 挠度⁃比强度斜率
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New Observation of Na2 4^3∑g^+ State by Pulsed Perturbation Facilitated Optical-Optical Double Resonance Spectroscopy
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作者 Zheng Chen Cheng-zhe Cui +3 位作者 Yao-ming Liu Li Li V. B. Sovkov V. S. Ivanov 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2006年第1期11-14,共4页
Sixty-five new vibronic levels of the Na2 4^3∑g^+ state have been observed in the 33900-35200 cm^-1 energy region above the potential minimum of the ground state by pulsed perturbation facilitated optical-optical do... Sixty-five new vibronic levels of the Na2 4^3∑g^+ state have been observed in the 33900-35200 cm^-1 energy region above the potential minimum of the ground state by pulsed perturbation facilitated optical-optical double resonance (PFOODR) fluorescence excitation spectroscopy. These new data fill the gap between the low-v levels mainly observed by continuous wave (CW) PFOODR spectroscopy and the high-v levels above the 3s+3d limit observed by pulsed PFOODR with predissociation detection, Molecular constants are fitted below potential shelf around the 3s+3d atomic limit with previously published data (mainly observed by CW PFOODR) and these new data. RKR potential curve has been calculated with the new constants. The constants are: Te= 32127.090 cm^-1,ωe=121.4099(0.20720) cm^-1, Be = 0.116287(0.0002300) cm^-1, Re=3.551 A, An error of the RKR potential curve of J. Chem. Phys. 108, 7707 (1998) is corrected. 展开更多
关键词 NA2 Triplet states PFOODR 4^3∑g^+ state STATE Rydberg states
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Biomass estimation of Shorea robusta with principal component analysis of satellite data
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作者 Nilanchal Patel Arnab Majumdar 《Journal of Forestry Research》 SCIE CAS CSCD 2010年第4期469-474,524,共7页
Spatio-temporal assessment of the above ground biomass (AGB) is a cumbersome task due to the difficulties associated with the measurement of different tree parameters such as girth at breast height and height of tre... Spatio-temporal assessment of the above ground biomass (AGB) is a cumbersome task due to the difficulties associated with the measurement of different tree parameters such as girth at breast height and height of trees. The present research was conducted in the campus of Birla Institute of Technology, Mesra, Ranchi, India, which is predomi- nantly covered by Sal (Shorea robusta C. F. Gaertn). Two methods of regression analysis was employed to determine the potential of remote sensing parameters with the AGB measured in the field such as linear regression analysis between the AGB and the individual bands, principal components (PCs) of the bands, vegetation indices (VI), and the PCs of the VIs respectively and multiple linear regression (MLR) analysis be- tween the AGB and all the variables in each category of data. From the linear regression analysis, it was found that only the NDVI exhibited regression coefficient value above 0.80 with the remaining parameters showing very low values. On the other hand, the MLR based analysis revealed significantly improved results as evidenced by the occurrence of very high correlation coefficient values of greater than 0.90 determined between the computed AGB from the MLR equations and field-estimated AGB thereby ascertaining their superiority in providing reliable estimates of AGB. The highest correlation coefficient of 0.99 is found with the MLR involving PCs of VIs. 展开更多
关键词 above ground biomass spectral response modeling vegetation indices principal component analysis linear and multiple regression analysis.
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